My question to you or anyone who is familiar with NFS on GFS, or GFS
in general, which of the following are still valid issues for the
current (6.1u4) version of GFS. If all or most of them still apply, I
can use this as motivation for my customer to strongly consider going
off NFS on GFS. Removing the NFS from our GFS cluster has been on the
cards for quite a while, but has not gained momentum due to lack of
information on the performance gains of such a move (very difficult to
gage) or the architectural problems/limitations of NFS on GFS (for
which the following extract is spot-on).

These have been worked on and some of them do have test patches ready to
address the issues. However, the changes are non-trivial and may involve
base kernel modifiction that we need to get upstream (community linux
kernel) acceptance. The efforts take time since we would like to do it
conservatively to preserve GFS1/2 stability. Unless the posted problems
have urgent needs (let us know), the current NFS-GFS development focus
is on failover (Red Hat bugzilla 132823).